Recent studies carried out at the University of Sheffield (Sheffield, England) have established a correlation between the onset of senescence and loss of viability in plants with a development of stable free-radicals which can be observed by Electron Paramagnetic Resonance (EPR) spectroscopy. We have explored a possibility of free-radical formation following root injury of corn seedlings. Free radical signals were detected by EPR spectroscopy at 9.5 GHz. In all cases, we have observed a single-line free radical signal (g-value around 2.004) superimposed with six lines EPR spectrum from Mn2+ ions naturally present in the plant tissues. We have determined a consistent increase in the intensity of single-line EPR signal after inducing the root injury. This signal is presumably attributed to a quinone-derived radical and, as speculated, is associated with stressed respiratory transport chains. Based on results of our observation, we can suggest that free-radicals reactions can be induced b y the root injury. Further, an appearance of free-radical signal in the root may serve as an indication of a stress, both natural and induced. If the precursors of observed free-radical signal can be determined (work in progress), this will improve the understanding of free-radical processes in plants following an injury.